Violence and aggressive behavior have become a national public health priority in recent years (Healthy People 2000 Review, 1992). One major underlying factor in aggression that occurs in social settings is that of conflict between individuals. To study social conflict and its potential aggressive manifestation, the Social Dilemma paradigm that involves mixed- motive interactions can provide a unique experimental context for analyzing group interaction processes and outcomes. Through a series of three experiments, this project will examine the impact of antecedent conditions of conflicts (i.e., cognitive and affective conflicts) and psychological contract violation on individual and group decision processes in various types of social dilemmas situations. The individual factors of the role of personality will also be investigated in one study. The present line of research that attempts to relate the areas of social conflict and social dilemmas represents a new avenue for understanding human social behavior in a group setting. The research outcomes will have applied implications for conflict in work groups or teams, aggression in the workplace, and conflict resolution in interpersonal and group situations.